Electric switch



May 17, 1966 w. A. RAsoR ET AL 3,251,956

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ELECTRIC SWITCH 9 Sheets-Sheet 6 Filed April 9, 1963 Mag,7 17, 19.66 w. A. RAsoR ET AL 3,251,956

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ELECTRIC SWITCH Filed April 9, 1963 9 Sheets-Sheet 8 May 17, 1966 w. A. RAsoR ET AL 3,251,956

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//V VFA/TOPS ATTO/Mfrs Fired Apr. 9, 1963, ser. No. 271,760 34 Claims. (cl. 20o- 14) This invention relates to electric switches generally characterized as rotary switches (sometimes also referred to as selector switches), pushbutton switches, and combination rotary and pushbutton switches, and to modular switch assemblies of the foregoing types. A rotary switch is one in which switch contacts are opened or closed upon rotation of the switch actuator; a pushbutton switch is one in which contacts are opened or closed by pushing the actuator; a combination rotary and pushbutton switch is one in which the contacts are opened or closed by a com bined pushing and rotation of the actuator.

The subject matter herein disclosed is based upon certain fundamental concepts some of which are: to provide a line of pushbutton, rotary, and combination pushbuttonrotary switches which utilize to a great extent similar parts and subassemblies; the design of the switches is such that the number of contacts can be readily increased by adding standardized subassemblies thereby avoiding the necessity of providing diffe-rent switch designs for different numbers of contacts; the design of the switches is such that the normal condition of the contacts,vi.e., open or closed, can be readily altered whereby a user having a switch whose normall contact condition is, for example, normally closed, can readily alter the switch to provide a normally open contact condition without the purchase of any new parts or a totally new switch; the design of the switches is such that they are highly compact and externally of such shape and dimensions as to allow an efficient 'design of control panels or boxes on or in which the switches are to be mounted; the switches are provided with terminals to which conductors may be readily connected without interference with other terminals, likelihood of accidental short-circuiting, or confusion as to which terminals are the proper ones for connection ofconductors to obtain the desired circuit control; and finally the line of switches are subject to manufacture and sale at competitively attractive prices.

A primary object of this invention is the provision of a switch body assembly for the aforementioned types of switchels, which comprises cooperating' stationary and movable contacts and a contact shifting part, all so designed, supported, and arranged that the same assembly may be used in either a rotary, a pushbutton, or a combination rotary and pushbutton switch, without any change except in the shape of the contact shifting surface of the contact shifting part.

Another object of the invention is provision of a modular switch made up of a tandem or stacked arrangement of removably connected individually complete switch body assemblies with mechanism connected to opposite ends of the switch for controllably actuating the individual switch body assemblies. By Varying the number of stacked switch body assemblies in a given switch, the total number of available switch contacts may be similarly varied.

United states Patent o 3 ,25 1,95 6 Patented May 17, 1966 Another object of the invention is the provision of each of the aforementioned three types of switches made up of three removably connected assemblies; an actuator assembly, a switch body assembly and a positioning assembly. The actuator assembly may be either the pushbutton, rotary, or combination pushbutton and rotary type; the switch body assembly may be for either a rotary, a pushbutton, or a combination rotary and pushbutton type switch; and the positioning assembly may be either for a detent type rotary switch, or for a spring-return rotary type switch either with or without detent means, or for a pushbutton spring-return type switch, or for'a combination pushbutton-rotary type switch.

Another object of the invention is the provision of a switch having a switchbody assembly which may be opened and the contact shifting part repositioned to give a different contact opening or closing sequence from that theretofore existing. For example, a pushbutton switch having what we term a universal contact shifting part, may be readily converted from one in which the contacts are normally closed, to one in which one contact is normally closed and another normally open, or in which the conj tacts are normally open simply by repositioning in the switch body assembly the contact shifting part. With a suitably shaped contact shifting part, the switch body assembly of a rotary type switch may be opened and the contact shifting part repositioned to provide a different sequence of contact operation. By utilization of differently shaped contact shifting parts any desired sequence of contact operation may be provided in a rotary switch of the character herein disclosed.

Another object of the invention is the provision of a switch body assembly as constructed that a plurality of suchassemblies may be connected in stacked or tandem relation, with the terminals for the contacts therewithin while exposed for connection of wiresthereto do not interfere with adjacent assemblies and are substantially protected from accidental short-circuiting by bare wires lying adjacent the switch.

Another object ofthe invention is the provision of a housing for a switch body assembly which is provided with independent chambers for each movable contact and each set of stationary contacts electrically insulating the contact-s against unintended short-circuiting therebetween.

Another object of the invention is the provision of a detent mechanism for a rotary type selector switch which may be readily altered to provide a greater yor lesser number of contact control positions and allow for diterent degrees of rotation of the switch actuator.

Other objects, advantages, and meritorious features will more fully appear from the specification, claims, and

accompanying drawings, wherein: y

FIG. 1 (Sheet l) is a cross-sectional View through a pushbutton switch embodying the invention showing the pushbutton assembly, switch body assembly and pushbutton spring-return assembly taken along the axis of the .switch on line 1-t1 of FIG. 3 and utilizing a cam caus- FIG. 4 (Sheet 3)-is a perspective view of a stationary contact assembly;

FIG. 4A (Sheet 2) is a side elevation of a movable contact arm looking in the direction of arrow 4A in FIG. 2;y

lFIG. 5 (Sheet 1) is a fragmentary cross-sectional view through a pushbutton switch body assem-bly but in which a cam is utilized causing the switch contacts to be normally open;

FIG. 6 (Sheet 1) is a side view of a pushbutton switch having a plurality of stacked or tandemly arranged switch body assemblies;

FIG. 6A (Sheet 1) is a top view of a pushbutton switch having :a plurality of `stacked or tandem'ly arranged switch body assemblies;

IFIG. 7 (Sheet 3) is an elevation of what may be termed a universal pushbutton cam;

FIG. 8 (Sheet 3) is Va right-hand end view of the cam of FIG. 7 showing the six cam lobes;

lFIG. 9 (Sheet 3) is a cross-sectional view taken on line 9 9 of FIG. 8;

FIG. l0 (Sheet 3) is a cross-sectional View taken ou line I0-10 of FIG. 8;

FIG. 11 (Sheet 3) is a cross-sectional view taken on l-ine 111-411 of FIG. 8; v

FIG. 12 (Sheet 3) is a fragmentary detail of the oating connection between the movable contact and the cam follower arm;

lFIG. 13 (Sheet 4) is =a cross-sectional view taken on line 13-'13 of FIG. 1 showing the positioning assembly;

FIG. 14 (Sheet 4) is a cross-sectional view taken on line 14-l14 of FIG. 13;

FIG. 15 (Sheet 5) is a cross-sectional view through a rotary switch embodying the invention taken alongV the axis of the switch and showing -the rotary knob assembly, switch body assembly, and detent positioning assembly;

FIG. 16 (Sheet 5) is a cross-sectional view through the detent positioning assembly of the vFiIG. 15 switch taken along the line I16--416 thereof;

=FIG. 17 (Sheet 6) is a cross-sectional v-iew through the i `detent positioning yassembly of the FIG. 16 switch taken along the line 117-17 thereof;

FIGS. 18, 19 and 20 (Sheet 7) show three different rotary cam configurations each in lassociation with a pair of movable contacts;

(FIG. 21,v (Sheet 8) is a fragmentary cross-sectional View through a combination rotary pushbutton springreturn switch showing the switch body assembly, detent positioning and spring-return mechanisms;

FIG. 22 (Sheet 8) is a fragmentary view of an elevation of a cam for use in the switch body assembly of FIG. 21;

FIG. 23 (Sheet 6) is a cross-sectional -view taken along the line 23-2'3 of FIG. 21;

FIG. 24 (Sheet 8) is a fragmentary cross-sectional view through a spring-return mechanism for a rotary switch; and

FIG. 25 (Sheet 9) is a cross-sectional view through a plurality of rotary switch body assemblies connected together in tandemor stacked relation.

In FIG. 1 and those gures ancillary thereto, the invention is shown embodied in a pushbutton type switch. In iFIG. 15 and those figures ancillary thereto, the invention is shown embodied in a rotary or selector type switch. In FIG. 21 and those figures anci-llary thereto, a combination pushbutton-selector switch is shown. With each of these three types of switches there are three Icommon assemblies, namely a switch body assembly and mechanism connected thereto for controllably actuating it comprising an actuator assembly and a positioning assembly. For convenience, reference numerals in the 100 Series refer to parts of a switch body assembly, those of the 200 Series refer to parts of au actuator assembly, and those of thel 300 Series to parts of a positioning assembly.

Except for the contact shifting part the switch body assembly is of identical construction whether used in the pushbutton, selector switch, or combination pushbuttonselector switch. The actuator and positioning assemblies differ somewhat as between the pushbutton, selector, or combination pushbutton and selector switches.

Pushbutton switch other parts of SBA100 changed correspondingly to provide for operation using such a single assembly control mechanism, in the instant and preferred embodiment such mechanism comprises the above mentioned individual assemblies '200 and 300. \A number of advantages, features, .and various inventive aspects of the subject matter disclosed herein require that the control mechanism be separated in individual assemblies as aforesaid, though certain other inventive concepts in the switch may not require such individualizat-ion of the assemblies.

The SBA is best shown in FIGS. 1 and 5 on sheet one, FIGS. 2 and 3 on sheet two, and in various figures of sheet three. It preferably comprises a dielectric housing 102 composed of a plastic having electrically non-tracking and arc-quenching characteristics. One such plastic that has been found particularly suitable is made by the Rostone Corporation, Lafayette, Indiana, under the trademark Rosite 3250. It is -a hot molded (thermosetting) material made up of mineral bers bonded together with a polyester resin. It has a high dielectric characteristic and good impact resistance. The SIBA housing is essentially a block of this or similar dielectric material .formed in rectangular shape, as viewed in FIGS. l and 2, having opposite parallel planar front and rear faces, respectively 103 and 104. Opposite side edges 105 and 106 are perpendicular to the front and rear faces while top and bottom edges 107 and 108 taper inwardly from the rear to the front face as shown best in FIGS. l and 6.

l"The block 102 comprising the switch housing has a central recess 109 (FIG. 2) therein opening outwardly through the rear face of the block to be substantially closed by cover 110 having a central opening 1111 therethrough. Such central recess also opens outwardly at 112 through the front face of the block in axial alignment with opening 111 on what might be considered the axis of the housing. Extending forwardly of the -front face 103 at the top and bottom edges are SBA positioning and aligning lugs or ears 113 and 1114, the former being larger than the latter, and at the rear face of the SBA block are complementary ear-receiving sockets I115 and 116. These Y ears of one SBA are adapted to t into the complementary sockets at the rear of another SBA to position the as- -semblies in proper axial and angular alignment as shown in FIGS. 6 and 25 where SBA30, S2 and 34 yare shown with -their respective ears and sockets in interfitted engagement.

Recess 109 is adapted to receive and house the switch contacts as well as the contact shifting part. The contact shifting part or cam CSP is disposed on the axis of the housing and on opposite sides of this part and adja- `cent the-reto are `the movable contacts generally indicated at 117 and 118. It'will be noted that the central recess is arranged symmetrically with respect to the axis of the housing. The walls of such recess are provided at opposite sides ofthe axis of the housing with a pair of sockets 119 and 120 opening through the rear face of the block to receive and rotatably support for pivotal movement one end of each of the movable con-tact lever arms 121i and 122. For this purpose each socket is` provided with a cylindrical inner wall 123 with the axis of the socket paralleling the axis of the housing and the axis of the contact shifting part CSP.

It will be noted that the wall of the central recess is 4also shaped to provide extending fingers 1.24 and 125'at opposite sides of the axis of the housing which are adapted to back up the inner ends of stationary contact means. Such contact means are disposed on opposite sides of the central recess and have terminal connectors exposed outwardly of the housing for connecting the contacts of the SBA in an electric circuit as hereinafter explained. Such stationary contact means comprise stationary contacts generally indicated in FIG. 2 at SC-1 and SC-4, and, while hidden in FIG. 2, other stationary contacts SC-2 and SC-3 are disposed directly in front of SC-1 and SC-2. The stationary contacts are arranged in pairs, to wit SC-1 and SC-2 comprising one pair and SC-3 and SC-4 comprising the other pair, with each pair adapted to be'bridged by a floating contact part at the free end of each movable contact lever arm, to cornplete a cir-cuit between the stationary contacts of each pair through the associated floating contact part. The stationary contacts SC-l and SC-2 are adapted'to be engaged and bridged by the movable con-tact part 126 floatingly carried at the free end of lever arm 122, while stationary contacts SC-3 and SC-4 are adapted to be engaged by the movable contact part 127 oatin-gly carried at the free end of the lever arm 121.

The stationary, or sometimes referred to as xed contacts, are disposed in the aforementioned pairs at common locations at opposite sides of the central recess and ,adjacent the sockets 1.19 and 120 which bearingly receive and support the movable contact lever ar-ms. It will be noted that intervening portions 124 and 125 of the block separate the sockets 119 and 120 from the adjacent pair of stationary contacts. The arrangement of sockets and pairs of stationary contacts is such that with the contact lever arms pivotally supported in the sockets, th'e arms extend across the central recess, alongside opposite sides of the contact shifting part, and terminate adjacent each such common location where the pairs of contacts are disposed.

The central recess 116 is provided with a plurality ofcontact conductorstrip receiving and supporting branch passageways disposed in spaced apart relation and electrically insul-ated from one another by intervening portions of the block. These branch recesses or passageways open outwardly through the rear lface of the block so that with the cover of the housing removed, the passageways are exposed as shown in FIG. 2.

Four such passageways are shown at 128, 129, 130 and 131. The passageways may be grouped in pairs in the sense that two of them, i.e. 128 and 129, open into the central recess at a common location at one side of the recess while another pair, i.e. 130 and 131, open into the central recess at another and common location at the opposite'side of the recess. With the cover 110 in place as shown in FIG. 3, the outer ends 128', 129', 130 and 131 of the passageways are exposed in the rear face of the block 1112. Each passageway is adapted to receive in a press t through the rear face of the block (when the cover is removed) one of the stationary contacts to support the same in fixed position in the block.

Each stationary Contact comprises a4 Contact conductor strip the inner end of which is exposed to the central recess at one of the aforementioned common locations and exhibits thereat a contact button, and the outer end of which is exposed through the rear lface of the block for connection to an electric circuit. The conductor strips are indicated at 132, 133, 134 and 135 for contacts SC-1, SC-2, SC-3 and SC-4 respectively. Strips 132 and 13S are identical as are strips 133 and 134. A description of 132 and 133 will therefore sufce for the others. The strips 132 and 133 are shown in perspective in FIG. 4 (Sheet 3) in their proper relative positions as they would appear in the SBA.

Strip 132 has at the inner end anextension arm 136 to which a contact button 137 is secured as shown.l

This strip, like the others, is formed of a suitably electrically conductive metal stamping such as medium hard brass with the button composed of nickel-silver alloy or any other well-known electrically and 'mechanically suitable metal, secured to the strip as by riveting, brazing or the like. The outer end of the strip is provided with means for connecting it to conductors of an electric circuit, and for this purpose a pair of laterally spaced apart connecting tabs or lugs 138 and 139 are provided which are inclined with respect to the remainder of the v strip to extend angularly out of the rear |face of the SBA as shown in FIGS. l, 2 and 6. A conductor provided with a female connector complementing the size and shape of the tabs, such as is schematically shown in FIG. l at 140 or 141, may be slipped grippingly over the tabs to connect conductors such as 142 and 143 to the stationary contacts.

The strip 133 is'provided with an extension arm 144 which is disposed at its inner end in spaced relation beneath the inner end of arm 136 as shown in FIG. 4 and a contact button 145 is mounted thereon. The outer end of strip 133 is provided with a pair of laterally spaced-apart connecting tabs or lugs 146 and 147 which are inclined similarly to tabs 138 and 139, to extend angularly out of the rear face of the SBA. An upstanding lug 148 is adapted to underlie cover 110 of the SBA to hold strip 133 from shifting upon withdrawal of connectors from tabs 146 or 147.

Buttons 137 andv 145 of the stationary contacts SC-l and SCI-2 face the companion floating contact part 126 of movable contact 118 to bebridged thereby to complete a circuit between the conductor strips 132 and 133. It will be noted from FIG. 2 that the pairs of connecting tabs 138 and 139 -for strip 132 are disposed spaced from the pair of connecting tabs 146 and 147 for strip 133 with a portion of the housing 102 disposed therebetween. When a plurality of switch body assemblies are secured together in stacked relation as shown in FIGS. 6 and 6A (Sheet l) the pairs of tabs and connectors received over them are even more positively separated by the interposition of the aligning lugs 113 and 114 therebetween and such tabs are substantially protected from all sides by their own SBA and the SBA juxtaposing it, from unintended engagement by loose conductors.

To facilitate insertion and support of the conductor strips in the passageways, rounded protuberances 159 and 169 of the walls of the passageways bear against the sides of the strips 'urging them toward the opposed side walls of the passageways.

The movable contacts 117 and 118 are of identical construction and are best shown in FIGS. 2 and 4A on Sheet 2. A description of one will suffice for both. lMovable contact 118 comprises a lever arm 122 which maybe formed of medium hard brass or any other suitable material, including a dielectric material, having an intermediate portion 149 transversely curved on a radius Iwhose center is measured from the axis of the SBA. One end lof such intermediate portion terminates in a cylindric bearing portion comprising a curled or substantially closed loop end 150 having an external cylindric surface mating with the cylindrical surface 123 of the socket 119 such that the lever arm is carried for closely guided swingable or pivotal movement by the socket with such movement being in a plane substantially perpendicular to the axis of the socket. Such closed loop end or bearing end 150 of the lever arm is offset from the remainder of the arm as shown at 150 and 150 in FIGS. l and 4A such that with the edge 151 resting or riding against the bottom 152 of the socket,

' the remainder of the lever arm is supported spaced from the bottom of the central recess as shown in FIG. 1.

lever arms in the sockets, thereby preventing `axial shifting of the arms in the sockets.

The floating part 126 at the free end of the lever arm has an elongated plate 156 (FIGS. 5 and 12) of a length sufficient to span the distance between and substantially cover in mating engagement the stationary -contact buttons 137 and 145. The back of the plate is provided with a shank 157 of square cross-section which extends in a loose lit through a square hole 157' (FIG. 4A) in the end of the lever arm. A head 158 on the4 shank, formed as by mushrooming the latter after insertion through the hole in the arm, serves to anchor the parts loosely together. The cross-sectional shapes of the shank and hole prevent any substantial rotation of the plate relative to the lever arm. By virtue of this iioating connection, any misalignment of the buttons 137 and 145 with the plate is compensated for, the plate being capable of sufficient rocking or tilting to insure proper full face-to-fa contact with the buttons. The plate 156 is of course formed of a suitably electrically conductive metal for completing a circuit between the buttons of the stationary contacts.

The movable contacts are yieldingly biased towardv and against the s-tationary contacts, and for this purpose each movable contact includes spring means in the form of a leaf spring sprung in place between the lever arm and the wall of the central recess to vurge the lever arm. toward the stationary contacts and toward the CSP. The leaf spring comprises a spring steel leaf 161 for arm 121 and leaf 162 for arm 122, one end of which is secured to the lever arm by insertion into the bearing end 150 of the lever arm rbetween the end of the loop and the opposing surface of the lever arm. The opposite end of the arm is bent as at 1613 lto provide a rounded surface for bearing against the side wall of the central recess. Intermediate opposite ends the leaf abuts the convex surface of the lever arm to urge the arm inwardly toward the stationary contacts. The end of loop 150 is provided with a shallow spring-receiving notch 164 (FIG. 4A) through which the leaf spring extends with portions 165 and 166 'of the end of the loop at opposite sides of the :notch serving to position the spring and prevent shifting thereof axially of the loop. The depth of notch 164 is slightly less than the thickness of the leaf 162 such that with the loop tightly closed with portions 165 and 166 bearing against the opposed surface of the lever arm, the leaf is sufficiently tightly gripped in the notch so that it will not work out of the loop or shift appreciably transversely of the plane of movement of the arm 122i.

Intermediate opposite ends of the lever arm and on the concave side thereof it is provided with a cam follower 167, the rear side of which is seen in FlG. 4A. The follower may be formed of a separate piece welded, brazed or otherwise secured to the arm or it may be formed integrally with the arm, as shown in FIGS. 2

and 4A, by suitably stamping the arm during its fabrication. In either form the cam follower is pyramidally shaped on a rectangular base whose major dimension extends lengthwise of the arm, and with the apex being omitted to form a flat face 168 bounded by four angularly related faces 169, 170, 172 and 173 (FIG. 4A) meeting each other and the face 168 along lines of intersection which have been radiused slightly to eliminate sharp corners. Each of these faces may at one time or another, depending upon the shape of the camming surface of the CSP and/ or the type of switch in which the SBA is utilized, act as a cam follower surface. This cam follower is a universal follower because it will properly function to shift the lever arm away from the stationary contacts or allow the lever arm to approach the contacts under the bias of the leaf spring with any of the wide variety of shapes of camming surfaces that may be formed on the CSP and despite the fact that the CSP may be shifted axially and/or rotated to effect shifting of the movable contacts.

The CSP for the pushbutton switch as well as for the other switches comprises the same basic structure and need differ only in the shape of the camming surface to effect various opening and closing sequences of the contacts whether the CSP be shifted axially or rotated.

Essentially the CSP comprises a cam supported for movement on the axis of the housing, the movement being either along the axis of the SBA and/ or rotatable thereabout. In effect the cam is moved on its own axis, which is coincident with the axis of the SBA, either reciprocably or rotatably, and in the case of the combination pushbutton-selector switch both movements of the cam are involved. The cam is removably supported in the housing. It includes coaxially extending means at opposite ends for removablyconnecting it to the mechanism at either side of the SBA for controllably actuating it as in the case of FIGS. 1 or 15, and/or to the cams of adjacent switch body assemblies when a plurality of such assemblies are stacked as in FlGS. 6- or 25 The CSP in every case includes a body 174, see Sheetv 3, of cylindrical form having coaxial means on opposite ends for slidably connecting the cam to adjacent cams and/or mechanism for controllably shifting the cam. Such means comprise complementary projection and socket means 175 and 176 which may be provided with complementary splines. While for merely a pushbutton type switch such splines may be unnecessary in some cases, the splines are preferably provided to simplify production of cam blanks thereby avoiding the necessity of distinguishing between blanks suitable for use in pushbutton switch body assemblies not requiring splines and other cases requiring splines.

ln any event the splines are a preferable means of allowing telescopic connection of adjacent cams or mechanism and preventing relative rotation therebetween. The socket 176 is sufficiently deep so that projection 175 of another cam may extend thereinto without bottoming when switch lbody assemblies' are juxtaposed as in FilGS. 6 and 25. The socket and projection of each CSP should be so sized Vrelative to each other that there is no relative rotation between adjacent telescopically connected cams, and the telescopic connection should be a push iit.

The CSP may be'and preferably is formed of a material having a low coeflicient of friction and adequate structural strength, such as nylon, Delrin or Teflon, the latter two being trademarks of E. I. du Pont de Nemours respectively for its tetrafloro etheylene resins and its acetyl resins. The CSP is preferably formed by injection molding using Delrin. The CSP shown in the drawings has twelve equally spaced spline grooves in the socket 176, and eleven spline teeth on the projection 175, with the teeth of projection 175 aligned with the grooves of the socket. While twelve spline teeth might be provided on projection 175, the omission of one tooth conveniently serves an index function as later explained. The portion of projection 175 at which the tooth has been omitted is indicated at 178. The body is provided with an index mark 177 radially opposite one of the grooves of the socket and `the omitted tooth 178i of the projection 175 whereby two cams may zbe readily telescoped together in preselected rotatably oriented positions.

The cam shown in the switch of FIG. l allows the switch contacts to be normally closed and is therefore identified `as N.C. CSP while the CSP of FIG. 5 maintains the contacts normally open and is therefore ident-i- Both cams are provided with an an- NC. CSP the inclined surface 179 is conical and slopes inwardly toward the rear. end (socket opening end) of the cam and the high lobe portion 180 is cylindrical and disposed at the base of the conical surface. 'In the case of N.O. CSP the camming surface is just reversed, i.e., surface 1181 is conical bult slopes inwardly toward the front end (projection 175 end) of the cam, and the high lobe portion 182 is cylindrical at the base of the cone.

Upon axially shifting N.C. 'CSP inwardly'or toward the rear of the switch (toward the left as viewed in FIG.

l) the cam followers 167 of each movable contact lever arm wi-ll ride the conical surface 179 causing the movable contacts to be shifted away from the stationary contacts opening the circuits between the contacts of each pair of stationary contacts. When the N.C. CSP reaches the limit of its inw-ard travel the high lobe surface 180 will underlie the cam follower 167 of the movable contact arms, holding the movable contacts at their wide open positions. Upon axial shifting of N.C. GSP outwardly (toward the right in FIG. 1) the cam followers of arms 121 and 122 will ride down the conical surface allowing the movable contacts under the tension of the leaf springs to reseat against the stationary contacts to tre-establish the circuit therebetween. By virtue of the spring 310 of lthe positioning assembly, hereinafter more fully described, the normal position of N.C. CSP is outwardly and in the position shown in FIG. 1. In this position the contacts Iare normally closed.

J ust the reverse of the foregoin-g operation obtains for N.O. CSP shown in FIG. 5. Here it will -be observed the contacts are normally open as the high lobe surface 182 underlies the cam follower 167 of each movable contact lever arm with the cam in its outward position. Upon axial shifting of the cam inwardly the cam followers ride down the inclined surface 1,81 allowing the contacts to close. When NiO. CSP axially shifts in lthe opposite direction t-he contacts :are again opened.

The cam shown in FIGS. 7-11 is what may be termed a universal cam and is therefore designated as U. CSP. Itts purpose is t-o allow both pairs of stationary contacts to be normally closed, or both pairs normally open, or one pair normally closed and the other normally open, depending upon the rotatably oriented position in which it is inserted in the switch body assembly. The pushbutton actuator 206 of the actuator assembly, hereinafter more fully described, is supported for axial shifting but held against rotation, and therefore with the spline projection 175 of the cam received in a complementary spline socket 212 of the actuator, rotation of the cam is prevented.

U. CSP is provided with a plurality of oppositely axia-lly inclined camming surfaces arranged about the cam at eqn-al angularly spaced-apart locations. Diametrically opposite camming surfaces may `be conveniently grouped in pairs as follows: rearwardly inclined surfaces 183 and 184; forwardly inclined surfaces 185 and 186; and oppositely inclined surfaces 187 and 188.

`By inserting U. CSP in the SBA in one rotatablyv oriented position, with the spline projection 175 in the spline socket 212 of the pushbutton actuator, such that the cammingsurfaces 183 and 184 are adapted to eng-age the cam followers 167 of the movable contact lever arms, the contacts will be normally open, and the cam lwill appear in cross-section taken along 9 9 of FIG. 8 with the cam in a SBA, similar to N.O. OSP in FIG. 5. Upon vdepression of the actuator button the contacts will be closed, while a return movement to the right under iniiuence of the return spring 310. will cause the contacts t-o reopen.

By withdrawing U. CSP from Ithe SBA and reinserting it in another rotatably oriented position such that the camming surfaces 185 and 186 are adapted to engage the cam followers 16'17 of the movable contact arms, the contacts will be normally closed, and the cam will ap- 'pear in cross-section vtaken along line 111-11 of FIG. 8

like N.C. CSP of FIG. l and will function similarly.

`On the other hand U. CSP may be inserted in the SBA in either of two other yrotatably oriented positions, to wit: such that surface 187 is adapted to ride the cam follower of arm 121 and surface 188 is adapted to ride the cam follower of arm 122, or vice versa. In the first of these rotatably oriented positions, contacts SC#3 and SC-4 will be'normally closed while contacts SC-l and SC-2 will be. normally open, and in the second rotatably oriented position contacts SC-3 and SCe4 will be normally open and contacts SC-l and SC-2 will be normally closed.

The mechanism for controllably actuating the switch body assembly of the pushbutton switch shown in FIG. 1 also serves to support the switch in a mounting panel. Such mechanism includes the actuator assembly 200, which extends through a suitably provided circular hole H (having a notch 221) in the mounting panel, and the positioning assembly 300 which cooperably with the actuator assembly 200 serves to effect shifting of the CSP.

Assembly 200 includes an actuator body or mounting body 201 having a cylindrical' bore 202 and a counterbore 203 within which is slidably received a cylindrical lactuator 206. A guideway slot 204 in the bore 202 is adapted to slidingly receive a corresponding rib 20-5 of the actuator 206. The rib extends forwardly along the actuator parallel its axis from a head portion 207 at the inner end of the actuator. The inter-fitting rib 205 in slot 204 prevents relative rotation between the actuator and mounting body 201 while allowing axial reciprocation of the actuator. The head 207 is adapted to abut the bottom of the counterbore 203 to limit outward movement of the actuator. The sliding fit of the actuator 206 in the bores 202 and 203 is sufficiently close so that it is supported for closely .guided but free travel in the mounting body 201.V

The rear end and face of the mounting body 201 complements the front face of a juxtaposed switch body assembly, being provided with sockets 208 and 209 to receive the aligning lugs 113 and 114 to properly rotatably orient the SBA on the rear face of the mounting body. A pair of threaded openings, only one of which is shown at 210 in FIG. l, are adapted to receive SBA retaining screws 211 and 212 to secure the SBA to the mounting body -in Hush mating juxtaposition. Each screw extendsv through a hole in the SBA housing 102 and is provided with an enlarged head 213 having a screwdriver slot 214 therein and a coaxial threaded socket 215 in the lhead for receiving similar screws of another SBA to secure the switch body :assemblies in tandem or stacked relation as shown in FIG. 6. t

The mounting body has a cylindrical bushing portion 216 threaded at its outer end to receive an externally knurled or the like nut 217. The bushing may be flatted as at 218 to receive and position a legend plate or locking ring 219 thereon, such plate having an inturned portion 220 which fits into slot 221 in the hole H through the mounting panel. A spacer 222 and dust seal 223 encircles the bushing at the back of the mounting plate. Tightening of nut 217 draws the mounting body tightly against the panel xedly securing it thereto. Another seal 224 set in an annular recess in the front of the -mounting body cooperates with the actuator to seal against the entry of foreign matter therealong into the bore 202.

A pushbutton 225 is threadedly received yin the outer end of the actuator 206 and is provided with a bore 226 and a counterbore 227 opening through the rear face of the button to removably .receive in a push iit a color code plate 228 having a shank 229.

The positioning assembly 300 for the pushbutton switch of FIG. l is adapted to urge the CSP and actuator 206 outwardly or to the right as viewed in FIG. 1. Such-assembly includes, as shown in FIGS. l, 13 and 14 (Sheet 1 1 Y 4) a cup-shaped houisng 309 preferably formed of a dielectric material such as the same'material from which the SBA housing is formed. Disposed within this housing is a helical compression spring 310 the larger end of which is seated against the bottom wall 311 of the housing, and the smaller end of which is seated against the head of a guide pin 312. The head of the pin which is integral with its shank 313 includes a wide iiange 314 having a centrally disposed nose 315. The flange 314 is circular. A shoulder 316 underlies the flange. Spring l310 is held under compression by a pin-retaining plate 317 shown in plan view in PIG. 13. The plate is generally circular but includes a pair of ear portions bent out of the plane of a central portion 31S which has a central aperture 319 therethrough. The ears, which are indicated at'320 and 321, abut shoulders 322 and 323 at opposite inside corners of the cup-shaped housing, to. be

. secured thereto by screws 324 and 325.

The shank 313 is unsplined and has a diameter that closely'ts the crests of the splines within the socket 176 of the CSP. Shoulder 316 is adapted to abut the end of the CSP surrounding the socket opening.

Spring 310 is so sizedthat while it will allow axial shifting toward the left, as viewed in FIG. l, of the CSP under finger pressure against button 225 of the actuator mechanism, it will return the CSP and button outwardly, to the right as viewed in FIG. l, .when operators finger is removed, and will thereby cause the contacts to shift as the contact followers follow the inclined surface of the contact shifting part.

Adjacent the corners of housing 309 opposite the screws 324 and 32S there are screw-receiving apertures extending through-the housing each having a beveled countersink in the rear face of the housing to receive therethrough screws 326 and 327 which are threadedly received within the threaded socket 215 of the screws 211 and 212 for holding the positioning assembly removably at the rear end of the SBA. The screws 326 and 327 of course extend through the openings 19@ and 191 inthe SBA cover 110 shown in FIG. 3. If desired the bottom of the housing 3139 may be provided with a central aperture 328 to allow' the Iinsertion therethrough of a member to push the CSP and pushbutton assembly to the right. However such aperture 323 is not likely to be used for this purpose as spring 310 is intended to return the CSP and pushbutton to the right under normal circumstances. Aperture 32SV nds its particular utility in connection with switches hereinafter describe-d wherein the same housing 309 is utilized, but without the spring 310, pin 312, .and retainer plate 317.

The inside of cover 119 is provided with a lug or shoulder 192, as shown in FiG. 3, which registers with a relieved area 193 of the block, so lthat the cover 11S can only be secured to the block in one rotatably oriented position. This insures that the index markings surrounding aperture 111 through the cover plate are in the properly oriented position on each SBA with which the cover plate may be assembled. For example, when using the universal cam U, CSP shown in FIG. 7, the index mark 177 is exposed through the cover as shown in FIG. 3, and by providing instructions to the installer of the switch, the manufacturer can indicate, foi example, that with the index mark set at the number one index position shown on the cover plate, switch contacts will be normally `closed. On the other hand with the index mark set at another specific position as indicated by the cover plate, the contacts might be normally open, or one might be normally open and the other normally closed. This is of `course even more important where there is a stacked assembly of SBAs and one wishes to check the stack to see what the contact sequence is, merely by removing the positioning assembly and successive SBAs, the installer can tell at a glance at the cover plate what the particular cam is s'et for.

The CSP is supported in the SBA for movement on the axis thereof as aforesaid, by a close fit between the cylindrical surface 194 thereof andthe edge of the hole 112 through the bottom of the SBA housing and the edge of the aperture 111 through the cover. The CSP is further supported by the push fit of its projecting end Vwithin the spline socket 212 of the actuator 206. In a stack of SBAs in a pushbutton switch, the splined projecting end 175 of each CSP is carried by the spline socket 176 of the adjacent CSP such that the successive cams are closely supported for movement on the axis of the stacked assembly.

Selector switch This switch is shown in FIGS. 15-20 and as hereinafter pointed out utilizes many parts identical to those heretofore described. The SBA is identical to the SBA of FIG. l except the camming surface of the CSP is different because the CSP rotates to effect opening 4and closing of the contacts instead of shifting axially as with the FIG. 1 structure. 1n addition, it is possible to provide for a variety of contact conditions at different positions of rotatable movement of the CSP', up to six different successive control positions being'shown, as distinguished from the two control positions possible with the pushbutton switch. The body 201' is identical to body 201 heretofore described. The actuator 206 has no longitudinal rib corresponding to rib 206 ofFIG. 1 so that it is free to rotate in the body-72411. Instead of a pushbutton 225, a selector knob 225' having a color code plate 228 is provided which may be of any suitable conguration to enable ready turning by an operator. Preferably the knob has a polygonal shank portion 230 slidably, nonrotatably received in a Vcorrespondingly shaped socket 231 in the actuator 206. A nut 217 somewhat similar to nut 217 is threaded onto the body 201 to secure the latter to the mounting panel. The nut includes an inwardly extending annular lip 232 and shoulder 232 which support the knob for rotation. A snap ring 233 received in a suitably provided groove in therknob locks the knob in the nut 217 against outward movement relative thereto making the knob and nut an individual assembly.

The positioning assembly has a housing 309 which is identical to housing 309 heretofore described. However the mechanism inside the housing 309' differs from that within housing 399. Within 309 is a detent mechanism whose function is to position and hold the CSP and knob at the position to which they are manually rotated by the operator. In the simplest form of selector switch operation, the knob is rotated between only two positions. At one position the contacts in the SBA are in one condition, for example, normally closed, while at the other position they might be, for example, normally open. The detent mechanism is provided with stop means limiting the rotation of the knob and CSP to these two positionsv with a spring detent for releasably holding the CSP and knob at either of these positions. However the detent mechanism may be repositioned in the housing 309 to give an additional position of rotation. thereby providing three possible contact conditions, for example, at one position both contacts Vmay be closed, at another position both may be open, and at the third position one contact may be closed and the other open. By slight modications Vof the detent assembly still further rotatable positions of lthe CSP may be obtained to provide for additional contact conditions.

The detent mechanism includes a detent plate 331 secured in housing 309 by screws 324 and 325. The plate is provided with a pair of dimples 332 and 333 which extend forwardly as shown in FIGS. l5 and 16 and which are disposed 6() degrees from each other about the center of the plate, .and equidistant from the vertical center line of the plate. Opposite these dimples are six additional dimples of similar size-334, 335, 336, 337,

from dimple 332. The pair of dimples 332 and 333 areutilized when the switch is to be a two-position selector switch and serve to position the CSP and selector knob at either of two positions to which the knob may be rotated. The remaining dimples are utilized when the selector switch is to have more than two positions.

Plate 331 is mounted on a hub 340 for rotation of the hub within the plate, the plate serving to support the hub in housing 309 and in turn a spline shaft 341 which extends into the CSP for rotation therewith. The shaft is provided with va flange 342 which abuts the rear face of the CSP to prevent rearward axial shifting of the CSP', the rear end of the shaft having a reduced diameter cylindrical bearing end 343 which tits hole 328 in the bottom of housing 309. One tooth of the splined shaft may be omitted to serve as an index for rotatable orientation of the shaft with respect to a CSP. Hub 34@ is splined to mesh with the splines of shaft 341 in a push tit. v

Fixed on hub 340 for rotation therewith is a locking plate 344 juxtaposing the detent plate 331 with the latter being held thereagainst by a snap ring or the like 345 which is received in a groove in the hub as shown in FIGS. 15 and 16. The hub has a shoulder 346 provided with a notch 347 into which an ear 348 of the locking plate extends to hold the plate. against rotation relative to the hub. The locking plate is spring-tensioned against the detent plate by virtue of a slot 349 in the locking plate which extends for -approximately 240 degrees around the plate to form a spring tab 350 at the center of the plate. This tab, in the manufacture of the locking plate, is bent angularly out of the plane of the plate such that when the locking plate and detent plate are juxtaposed on the hub as shown in FIG. l5, a dimple 351 on the locking plate is yieldingly tensioned against the .detent plate and into a dimple of the latter when the same is aligned with dimple 351. By turning the selector knob 225' the locking plate is caused to turn relative to the detent plate, the peripheral portion of the latter yielding or shifting away from the locking plate to allow dimple 351 to ride out of the dimple in the detent plate and traverse the angular distance to the next adjacent dimple in the detent plate at which dimple 351 will spring thereinto and the operator will immediately `again sense an increased resistance to turning of the selector. Each point during rotatable movement of the knobA 225' at which the operator encounters marked resistance to further turning will indicate a location at which the switch contacts are at a control position. At each such position Athe nesting dimples of the respective locking and detent plates will hold the CSP and knob against further unintended rotation.

To limit rotation of the CSP and knob 225 the detent plate 331 is provided with a pair of diametrically opposite stop ears 352 and 353 whichextend rearwardly and overhang the peripheral edge of the locking plate 344. Plate 344 has a plurality of peripheral outwardly extending rangible stops or lugs 354, 355, 356, 357 and 358 disposed in angularly spaced-apart relations and de- 4ning therebetween diiferent degrees of allowable angular travel of the locking plate.

Stops 356 and 357 are disposed at their edges 359 and 360, 60 degrees apart and will will limit, by virtue of the interposition of stopping ear 352, rotation of the locking plate, and hence the CSP', to 60 degrees of angular travel. When the locking plate is disposed within the housing as shown in FIG. 17, angular travel of the CSP will be limited to 60 degrees and three control positions will be effective, namely, when dimples 335, 336 and 337 are successively engaged by dimple 351 of the locking plate. If stop 357 is removed then another 3'0 degrees of rotation of the locking plate will be afforded, with the consequent provision of four control positions for the CSP. If stop 356 is removed then an additional 30 degrees of rotation is allowed, and five control positions for the CSP are provided. If stop 355 is removed, then still another 30 degrees, altogether now 150 degrees, of rotation is allowed, and six control positions for the CSP are provided, each position 30 degrees from the next adjacent position.

If none of the stops are removed from the locking plate, but instead it is removed from the hub (of course rst removing snap ring and detent plate) and replaced therein at 180 degrees from the position Ishown in FIG. 17, then stops 356 and 357 will cooperate with ear 353 of the detent plate limiting rotation to 60 degrees, but also providing for nesting of dimple 351 in either dimple 332 or 333 of the detent plate, to provide two control positions 60 ydegrees apart for the CSP'.

The locking plate and detent plate are formed of any suitable suiciently spring-like and wear-resistant material, and either medium brass or beryllium copper are satisfactory. The housing 309' is secured to the SBA' in the same fashion as is housing 309 secured to the SBA of FIG. 1. The splined shaft 341 is inserted in the hub 340 such that the omitted tooth Iof the splines is disposed opposite either one of two index marks 17711 or 177b of the locking plate.

By the proper selection or design of the CSP a wide variety of possible contact conditions may be obtained with the selector switch. Also, the rotatably oriented position in which the CSP' and shaft 341 are telescoped together will determine the sequence of operation of the contacts.

FIGS. 18, 19 and 20 show three possible configurations of the CSP looking at the rear end of the CSP', for example, along line 18-18 of FIG. 15. A number of different configurations are possible and the three shown are merely examples. The rear face of the cam carries one or more degree index marks. With the shaft 341 telescoped inthe cam of FIG. 20 such that the omitted tooth portion of the shaft is opposite the Zero degree index mark of the cam and the index mark 177a of locking plate 344,v the contacts 1 (SC-1 and SC-2) and 2 (SC-2 and SC-3) will be open when the lug 360 of the locking plate abuts stop ear 352 (dimple 351 nests in dimple 388), and will be closed when the selector knob and cam are rotatedv in the direction of the arrow of FIG. -20 to nest dimple 351 in dimple 337, 336, 335, or 334. -Of course to rotate the cam to positions in which dimple 351 will nest in dimple 335 or 334 of the detent plate, ears 355 and 356 must be removed.

In table 20a the sequence of contact positions is shown when the shaft 341 is telescoped in the cam and the cam rotated as above described. Numerals 1 and 2 at the left end of the table correspond to contacts 1 and 2 schematically shown in FIG. 20, the O marks in the table indicating open Contact and the X marks indicating closed contact. The numerals 1, 2, 3, 4, 5 at the top of the table indicate the successive control positions of the cam as represented by the dimple 351 nesting respectively in detent plate dimples 338, 337, 336, 335 and 334.

In table 2Gb the contact conditions are shown when the shaft 341 is telescoped into the cam of FIG.'20 such that the omitted tooth portion of the shaft is opposite index 30 on the cam. In this instance, at each of the five rotated positions -of the cam, the contacts are closed. In table 20c the contact conditions are shown during the same sequence of cam rotation as with tables 20a and 20b, and here the shaft 341 and the cam are telescoped together such that the omitted tooth portion is opposite index mark 60 of the cam. It will be appreciatal that with the elimination of lug 375 a six position sequence may be provided.

FIGS. 18 and 19, each with their accompanying tables, show contact conditions arising from the shape of the cams and the rotatably oriented position of telescoping together shaft 341 with the respective cams. It is apparent that depending on the shape of the cam and the rotatably oriented position of cam and detent shaft, an extremely wide variety of sequential contact conditions may be obtained, and that with any given cam a number of different sequences of contact opening or closing is possible.

Cams of different shapes to give rise to varying sequential orders of contact opening `and closing while of value in a switch utilizing only one SBA' as shown in FIG. 15, are also of value in a stacked arrangement of switch body assemblies when used in a selector switch such as shown in FIG. 25. In this figure a plurality of switch body assemblies are connected together in tandem to be conjointly operated upon rotation of the selector knob, not shown. With CSP'1, CSP-2, CSPLZ and CSP-4 of FIG. 27 each having suitable index marks at the rear face similar to the cams of FIGS. 18, 19 and 20, and with the spline projection of each having a tooth omitted or some other index indicia, and with the cams of any desired camming surface configuration and rotatable orientation relative to each other for telescopic connection, any desired sequence of contact operation may be provided for the-selector switch assembly. For example, at one rotated position of the selector knob 4the contacts of SBA1 may be closed, those of SBN-2 may be open, one pair of contacts may be open and .the other closed in SBA-3, and in SBA'4 both contacts may be closed, while at another rotated position a different series of contact conditions may obtain. By disconnecting the vfour switch body assemblies and rotatably reorienting the cams relative to each other a different sequence of contact operation ffor the entire assembly may be obtained. It has been found that by utilizing different rotatably oriented positions of telescopic connection of a series o-f cams, a large number of combinations of contact operation and sequences of operation are possible with only a few different cam shapes. Through the preparation of suitable tables for each of the different carn shapes and combinations of such shapes in various rotatably oriented positions of telescopic connection, the various combinations of contact conditions and sequence of contact operation may be readily determined. As a consequence, a switoh'manufacturer constructing a line of selector switches following the teachings of this disclosure may provide for any variety of combination of contact conditions and sequence of contact operation likely to be required by a'customer with the only difference in parts being the shape of the camming surface of the cam.I With a number of differently shaped cams in stock, the customer requirements may be satisfied by the proper selection of cams and proper rotatably oriented connection thereof together, which may be determined from the previously prepared tables showing the possible combinations andV sequence of contact operation. Similarly, a user of the selector switch may, by changing the rotatable orientation of the CSP relative to the detent shaft or relative to another CSP where more than one SBAis utilized in the switch, alter the contact position of the switch or sequence of contact operation.V

It is apparent -from the foregoing that the telescopic connection of the CSP with the detent shaft through the use of a splined socket, and the telescopic connection of cams having cor-responding splined sockets and projections leads to a simple, readily alterable assembly which can provide an unlimited variety of possible contact conditions and sequence of contact operation. It is also apparent that because the only difference between switch body assemblies [for selector switches which give rise to different contact conditions and sequence of operati-on is in the shape of the camming surf-ace of the cams or the rotatable orientation of the cams and detent shaft at the time of their telescopic connection, substantial savings in cost are possi-ble. Even the cam blanks may be and` preferably are ofidentical shape, only the shaping of the camming surfaces requiring different manufacturing operations.

In the FIG. 25 assembly the switch bodies SBALI, SBN-2, etc. are, of course, identical in structure to the SBA of FIG. l5 differing only in the particular CSP' that may be utilized. The switch bodies are removably secured together by screws (not shown) similar to screws 211 and 212 of the puslrbutton switch with the screws of SBA2, for example, threading into the head-end of corresponding screws of the SBA-ll. As the various contact shifting parts or cams CSP'1, CSF-2, etc. are telescoped together in splined interfitting relation, a single mounting body such as 201 is utilized which supports the stacked `arrangement of switch body assemblies from a panel.y A single positioning assembly of a construction identical tov that shown in FIGS. l5, 16 and 17 may be utilized.

Pushbutton-seleczor switch In FIIG. 21 a combination.pushbutton-selector switch with a spring return :is shown. In such a switch a mounting body and selector knob of the type generally shown in FIG. 15 is utilized as well as a similar SBA', it being of course obvious that the selector knob must be axially displaceable inwardly as well as rotatable. The CSP has a differently shaped camming surface than any heretofore mentioned because the switch contacts are to be actuated by a combination of axial shifting and rotation of the cam. For example, the cam may have a. camming surface configured such that one of the movable contact lever arms is shifted when the selector button pushed and the other contact lever arm is only shifted when the selector button is thereafter rotated while held depressed. A different camming surface configuration might require a depression and rotation of the selector knob while held depressed to effect any shifting of either `or both of the lever arms.k Other configurations of the camming surface may give rise to other forms of contact operation with this type switch.

To limit rotation of the cam a hub 340', detent plate 331 and locking plate 344 of the type described in connection with FIGS. 15, 16 and 17 are utilized in the FIG. Z1 construction. The housing 309 is similar to housing 309 except as herementioned. It is of a somewhat greater axial length than housing 309 and has a central internal boss 361 with an unsplined aperture therethrough sized to rotatably support the splined shaft 362 and is further provided with a rib 363, see FIG. 23. The detent plate is secured to the bottom or rear of the housing by screws similar to screws 324 and 325 of FIG. 16. Rib 363 cooperates with a torsion or return spring 364 which serves to rotatably reposition .the cam upon release of the selector knob ,by the operator. The spring encircles the boss 361 and its opposite ends are bent to extend radially outwardly of the spring axis and sprung into embracing relation over the rib as shown in FIG. 23. Mounted in splined connection on shaft 362 is a return finger having a shaftembracing plate portion 365 and a laterally bent finger part 366 intenposed between the ends of the torsion spring as shown in FIG. 23. Upon rotation of `the shaft 362 in either direction upon rotation of the selector knob and contact shifting part, one end of spring 364 will move with the finger portion 366 to return the sha-ft to its initial position upon release of the knob. Where the detent plate and locking plate are assembled to allow shaft rotation in either direction from its initial position, the spring acts as a centering spring.

yIn the` FIG. 21 construction the hub 340 and return Ifinger are a slip, though splined, fit on the shaft, whereby the shaft may shift axially through them upon depression of the selector knob. Secured to the rear face of housing 309" is a positioning assembly 300 similar to the assembly 300 of FIGS.V l, 13 and 14.V It differs therefrom only in that the shank 313 of guide pin 3112 is of a smaller diameter than shank 313 as it must fit a smaller socket (unnurnbered) in the left end of shaft 362.

Spring 310 serves to return .the shaft and CSP to the right following axial shifting to the left under depression of the actuator. 'Ihe fit of shank 313' in the socket at the left end of shaft 362 and the encirclement of the small end of spring 310 about nose 315 is sutciently loose so that the shaft may rotate without appreciable resistance being offered by spring 3110.

In the FIG. 21 embodiment shaft 3612 is shown as extending completely through the CSP and into the actuator 206', the CSP" having a splined bore therethrough with which the shaft meshes. A shoulder 342 on rthe shaft, which may be a snap ring received in 4a suitably provided groove in the shaft, abuts the CSP" to hold it against the actuator 206. It will be apparent, however, that the CSP" may be similar to the cams heretofore described in having a splined socket at one end and a splined projection at the other end with shaft 362 being shorter and telescoped into the socket and the splined projection of the cam projecting into the actuator. Such latter construction is preferred, the one shown being an alternative.

The camming surface of CSP shown in FIGS. 21 and 2 2 is merely one example of many possi-ble configurations. Such cam has an axially inclined surface 179' and a radially tapering or eccentric cam lobe 180', each of which occupies but a portion of the total circumference of the cam. IIt will be noted from `FIG. 21 that the relative axial position of the cam followers (one. of which is shown in phantom) and surface 179 is such that merely rotation of the cam without axial depression will not cause a cam follower to ride up surface 179. Also, -the normal rotatably oriented position of the cam is such in relation to the cam followers that an axial shifting of the cam alone will not serve to shift a contact lever arm. yHowever by rotating the cam, lobe 180 rides against one of the cam followers to shift the associated lever arm away from its companion stationary contacts, and then while holding the cam in such rotated position if the actuator is depressed, surface 170 will ride 'beneath the cam follower of the other lever arm shifting it away from its companion stationary contacts. The switch of FIG. 21 havinga cam of the configuration described therefor has both contacts normally closed, one set being opened upon rotation Vof the cam and the other set upon axial depression while the cam is held in its rotated position.

As will be apparent different cam configurations will give rise to different contact conditions and sequences of contact operation. `It is also apparent that by stacking similar switch body assemblies a greater number of contacts may be provided, and that by proper design of cams for a stacked assembly a wide variety of contact conditions and sequence of contact operation for the switch may be attained.

Self-returning selector switch In FIG. 24 a self-return mechanism for a selectorswitch is shown. The housing 309-3 is similar to hou'sing y3019 except 4that the bottom wall instead of having an aperture completely therethrough is closed as at 370 and a shoulder 372 is provided against which the end of shaft 341 bears. Shaft 341' is similar to shaft 341v of FIG. 15, and a spring-return mechanism of the character disclosed in FIG. 21 is fitted on the shaft just behind hub 340. With the positioning mechanism of the FIG. switch modified as shown in FIG. 24, rotation of the actuator will be counter the bias of the return spring 364 and upon release of the actuator the spring will return the shaft, cam and actuator to their original positions.

What is claimed is:

1. -An electric switch comprising: a housing, a stationary contact in the housing, a movable contact supported 4in the housing for movement toward and away from the stationary contact and yieldingly biased theretoward to make a circuit therewith, a contact shifting part supported for movement in the housing and having an inclined camming surface cooperable with the movable contact to shift the same away from the stationary Contact upon movement of the cam, and mechanism for con- `and complementary splined projection and socket means and said mechanism includes a rotary knob at one side of the housing slidably interconnected with a spline of one of said means, and said mechanism further includes a rotary positioning device at the opposite side of the housing slidably interconnected with a spline of the other of said means.

3. The invention as defined in claim 2 characterized in tha-t said rotary positioning device includes a return spring yieldingly biasing said cam counter rotation of said knob.

4. An electric switch comprising: a housing, a stationary contact in the housing, a movable contact supported in the housing for movement toward and away from the stationary contact and yieldingly :biased theretoward to make a circuit therewith, a cam supported for movement in the housing on a xed axis and having a camming surface tapering axially of the cam, said movable contact pivotally supported upon an axis extending substantially parallel to the fixed axis of the cam, and mechanism for shifting the cam axially disposed externally at opposite sides of and removably secured to the housing with portions removably mechanically connected with opposite ends of the cam.

5. In a switch: a housing, a pair of fixed `contacts in the housing, an arm in the housing, means in the housing for supporting the arm at one end for pivotal movement toward and away from the fixed contacts, means for biasing the arm toward the fixed contacts, a bridging contact on the other end of the arm with means oatingly mounting the bridging Contact on such end of the arm to engage the fixed contacts and make a circuit therebetween, a cam supported for movement in the housing adjacent said arm and having an inclined camming surface engaging said arm to pivot the same away from the stationary contacts upon movement of the cam, and terminal means supported in the housing and connected to the xed contacts for connecting the same to an external electric circuit.

6. An electric switch comprising: a housing, a stationary contact in the housing, a movable contact supported in the housing for movement toward and away from the stationary Contact and yieldingly biased there- .toward to make a circuit therewith, a cam supported for movement along a xed axis in the housing and having 'an inclined camming surface cooperable with the movable contact to shift the same away from the stationary contact upon movement of the cam, actuatormechanism removably secured externally to one side of the housing and having an axially shiftable button removably mechanically connected with one end of said cam, and cam positioning mechanism removably secured externally to an opposite side of the housing and having a spring loaded part mechanically connected with the opposite end of the cam and yieldingly biasing the cam axially toward the button.

7. An electric switch comprising: a housing, a stationary contact in the housing, a movable contact supported in the housing for movement toward and away from the stationary contact and yieldingly biased theretoward to make a circuit therewith, a cam supported for movement in the housing along a xed axis and cooperable with the movable contact to shift the same, said cam having at one end a coaxial splined connecting portion, cam4 actuating mechanism removably secured externally to one side of the housing in coaxial alignment with the cam and having an axially shiftable part fixed against rotation and provided with a splined portion removably interfitting with the splined portion at the end of the cam, cam positioning mechanism removably secured externally to an opposite side of the housing and having a spring loaded part connected with the other end of the cam and yieldingly biasing the cam axially toward the actuator-mechanism, and said cam including a plurality of angularly spaced apart camming surfaces one of which is operable to shift the movable contact away from the stationary contact upon depression of said part axially against said spring bias, and another of which is operable when the cam is connected to said part at a different rotatably oriented position, to shift the movable contact toward the stationary contact upon depression of said part against said spring bias.

8. In an electric switch assembly: a switch housing comprising a block of dielectric material having a central recess therein opening outwardly through a face of the block, said block provided with a plurality of conductor strip receiving and positioning recesses disposed in spaced apart relation and electrically insulated from one another by intervening portions of the block and opening outwardly through a face of the block, said block provided with a terminal conductorY strip receiving passageway for each terminal recess extending between its terminal recess and the central recess with pairs of passageways opening into the central recess, a terminal in each terminal-receiving recess having a conductor strip extending through the associated passageway to the central recess, a stationary contact on each strip exposed to the central recess, said central recess having wall portions shaped to pivotally support one end of a movable contact lever arm, a movable contactlever arm in the central recess pivotally supported at one end by said wall portions and provided at the opposite end with a bridging contact for bridging a pair of stationary contacts when the arm swings theretoward, said housing provided with an aperture opening through the bottom of the central recess outwardly of the opposite face of the housing, a cam in the central recess having a camming surface cooperable with the movable contact lever arm to swing the same upon shifting of the cam, mechanism for shifting the cam. secured to the outside of the housing at said opposite face thereof, means extending through said aperture connecting the cam to said mechanism, and cover means extending over the open ends of the recesses.

9. In an electric switch assembly; a block of dielectric material having a central recess opening Voutwardly through a face of the block, a cam in said recess, said block provided with a plurality of terminal-connecting conductor strip receiving and supporting passageways opening laterally outwardly through such face of the block and disposed in spaced apart relation and communicating in pairs with a central recess at a plurality of spaced apart common locations, a rigid terminalconnecting conductor strip laterally slidably received and supported in each of said passageways and provided at the inner end with a fixed contactV disposed in spaced apart adjacency with a companion fixed contact of another strip at the said common locations about the central recess with the strip having at its other end a terminalconnecting portion exposed through such face of the block for connection with a conductor thereto, said block shaped at spacedapart locations about the recess to provide a plurality of individual means for pivotally supporting a plurality of movable contact lever arms with one such means for each such arm, at least one such lever arm disposed inthe recess and supported at one end by said means and extending across the recess alongside the cam and terminating at its free end adjacent one of said locations, a bridging contact onV the free end of the arm for engaging and bridging the fixed contacts at said location, said arm provided with -a portion for riding a camming surface -of the cam, and spring means in lthe central recess yieldingly biasing the lever arm toward the cam.

10. In an electric switch: a housing, a cam supported for movement on a fixed axis in the housing, a plurality of pairs of fixed contacts in the housing arranged about the axis of movement of the cam in radially spaced position from the cam, a plurality of operably independent movable contact lever arms each swingably supported at one end in the housing for movement about an axis substantially paralleling the axis of the cam with t-he arms extending along opposite sides of the cam and each terminating at its free end adjacent a pair of the fixed contacts, a bridging contact on the free end of each arm-for bridgingly engaging a pair vof the fixed contacts to complete a circuit therebetween, each arm having a cam follower portion intermediate opposite ends for riding a camming sur-face ofthe cam, said cam having a radially outwardly facing camming surface radially opposed to the arms and operable to shift the arms radiallyV upon movement of the cam, spring means in the housing for yieldingly biasing each arm independently inwardly toward the cam, and each of said fixed contacts having terminal-connecting portions extending outwardly of the housing for connection of the fixed contacts in an electric circuit.

`1&1. The invention Ias defined in claim 10 characterized in that said cam is axially shiftable in the housing and spring means are provided for yieldingly biasing the cam toward a first axially displaced position and actuator means are provided for axially shifting the cam counter said spring means to a second axially displaced position, and said camming surface tapers axially of the cam to shift the arms radially of the cam during axial shifting l thereof.

12. The invention as defined in claim 10 characterized in that one portion of the camming surface opposite a cam follower of one arm tapers axially inwardly from one end of the cam toward the other end while another portion of the camming surface opposite a cam follower of another arm tapers axially outwardly lfrom said one end of the cam toward the other end whereby axial shifting of the cam simultaneously shifts one arm radially outwardly and another arm radially inwardly.

13. A switch body assembly comprising: a dielectric housing having a recess therein opening outwardly through a face thereof, a cam supported for movement centrally in the recess, a pair of arms in the recess on opposite sides of the cam and .each supported at one end for swingable movement in a plane substantially perpendicular to the axis of movement of thecam, each arm having a cam follower portion intermediate the ends of the arm confronting the cam, and a pair of fixed contacts for each arm disposed in the recess to be engaged and bridged by the free end of each arm, and spring biasing means in the recess for each arm yieldingly and urging the free end of` the arm toward its associated pair of fixed contacts.

14. A modular switch body assembly for stacking in axial ,alignment with corresponding assemblies comprising: a block of dielectric material having opposite parallel faces for facial juxtaposition in a stack with corresponding blocks, said block having a central recess therein opening outwardly through such faces for alignment with corresponding recesses of adjacent blocks in a stack, -a cam supported in the recess for movement on an axis extending perpendicular to said faces and having coaxially arranged portions at opposite ends for engaging corresponding portions of cams of corresponding assemblies disposed in stacked relation at opposite faces of theV block, two pairs of -fixed contacts disposed in the recess at opposite sides thereof, a pair of arms in'- the recess on opposite sides of the cam with each arm swingably supported at one end in a wall of the recess adjacent one pair of fixed contacts and electrically insulated therefrom by an intervening portion of the block and extending 2.1 across the recess along side the cam and terminating at its free end adjacent the opposite pair of xed contacts,

means at the free end of each arm for bridgingly engaging the fixed contacts adjacent such end of the arm, each arm having a cam follower portion intermediate its opposite ends for riding a camming surface of the cam, spring means in the recess yieldingly biasing the free ends of the arms toward the iixed contacts, and terminal connectors extending outwardly of the block and connected at their inner ends to the fixed contacts.

15. An electric switch comprising: a switch body assembly vhaving a dielectric housing containing a pair of stationary contacts and a cooperating movable contact arranged to make and break a circuit between the stationary contacts, a cam cooperable with the movable Contact to shift the same, an .actuator assembly having a housing removably secured to one side of the switch body assembly housing and supporting mechanism cooperating with the cam to shift the same, and a cam positioning assembly having a housing 'removably secured to the opposite side of the switch body assembly housing and containing mechanism cooperable with the cam to position it.

16. A modular stack switch comprising: a plunality of Asubstantially closed individual switch housings remova-bly :secured together in aligned tront-to-rear facial juxtaposition, a cam in each housing supported for movement on an axis of the assembly with the cams removably mechanically -connected for conjoint dependent shifting, mechanism secured to one end of the assembly and connected to the cam of the adjacent switch housing for shifting it and in turn the cams in the other housings, cooperating stationary and movable contacts in each housing with terminal -connectors exposed outwardly of the housing for connecting the `contacts in an electric circuit, said movable contacts including spring means yieldingly biasing the movable contacts toward the stationary contacts, and each movable Contact disposed vadjacent a cam and disconnectably engaged therewith to be lshifted thereby counter the spring bias out of engagement with an associated stationary contact upon movement ofthe cam.

17. A modular stack switch comprising: a stacked plurality of individual corresponding switch body assemblies removably secured together in aligned front-to-rear facial juxtaposition, a cam in each :body assembly supported in axial alignment with the cams in the other assemblies, means connecting together `the cams of adjacent assemv blies for conjoint dependent movement, companion stationary and movable contacts in the assemblies with the movable contacts cooperating with the cams to be shifted thereby toward and -away from the stationary contacts, actuator mechanism connected in axial alignment to one end of the `aligned stack of assemblies and 'having an actuating part connected to the cam of the ladjacent assembly for shifting it and in turn the cams of the other assemblies, andcam-positioning mechanism lsecured to the opposite end of the aligned stack of assemblies and having 'a cam-positioning part connected to the cam of the adjacent assembly to position it and in turn the cams of .the other assemblies,

18. A switch housing for a modular stack-type electric switch comprising: a `block of dielectric material having opposite front and rear faces with the front face having a greater transverse dimension than the rear face such that when corresponding blocks are stacked in aligned front-to-rear facial juxtaposition the front face of one has lface portions exposed beyond `the edge of the juxtaposed rear face of the other, and said block internally recessed to receive and support switch mechanism and terminal connecting lugs with such internal recessing opening through said front face portions to expose terminal connecting lugs supported in such internal recessing :for attachment of terminal-s thereto when a plurality of such blocks are in the aforesaid stacked relation.

19. The invention as defined in claim 18 characterized in that said block is provided with corresponding lug and socket portions for establishing properjuxtaposed alignment with Aa corresponding block.

2t). The invention as defined in claim 18 characterized in that said block has a side edge tapering inwardly from the front face to the rear face to overhang in spaced partially covering relation the said front face portions of a corresponding block when the blocks are in the aforesaid s-tacked relation.

21. A switch housing for an electric switch comprising: Ia block of dielectric material having a central recess opening -outwardly through a face of the block, said block provided with a plurality of terminal-connecting conductor strip-receiving passagewaysdisposed in spaced-apart relation and electrically insulated from one another by intervening portions of the block `and opening outwardly of the block in such spaced-apart relation and opening inwardly in pairs at a plurality of Ispaced-apart common locations into said central recess whereby when terminal-connecting conductor strips are disposed in such passageways they are exposed in pairs to said central recess at such spacedyapart locations, said block shaped at spaced-apart locations about said central recess to provide a plurality of individual means for pivotally supportinga plurality of movable contact lever arms with one such means for each such arm, each such means being disposed on yan opposite side of the recess from one of said common locations whereby a movable contact lever arm when supported thereby may extend across the recess toward such common location.

22. The invention as defined in claim 21 characterized in that said passageways open outwardly through the .same face of the lblock as the central recess spaced laterally from the central recess, and a dielectric cover closes the centr-al recess at such face of the block.

23. The invention as defined in claim 21 characterized in that said face of the block is the front face and the block is provided with a parallel rear face of lesser transverse dimension than the front face such that a corresponding block may be stacked in front-to-rear facial juxtaposition with portions of the front face of the block exposed beyond the edge of the juxtaposed rear face of the other block, and said passageways in `the block open outwardly through said exposed portions of the front face to expose for connection terminal-connecting conductor strips disposed therein.

24. A switch housing for an electric switch comprising: a block of dielectric material having a central recess opening outwardly through a face of the block, said iblock provided with ya terminal-connecting conductor strip-receiving passageway opening outwardly of the 4block and inwardly into said central recess, said block shaped at said central recess to provide a cylindrical socket opening laterally into the central recess ffor receiving and pivotally supporting the cylindrical end portion of a movable contact lever arm, said cylindrical socket disposed at an opposite side of the `central recess from the point at which said passageway opens into the central recess such that a lever arm when pivotally supported in the :socket will extend across the recess to the opening of said passageway, and a closure adapted to cover said central recess.

25. In an electric switch; a pair of stationary contact means, a pair o-f movable contacts supported in opposition to the stationary contact means for independent movement toward and away from the pair of stationary contact means and biased theretoward, a contact shifting part supported adjacent the pair of movable contacts for axial shifting in opposite directions, means for holding said part in either of two rotatably oriented positions during axial shifting, said part having a plurality of circumaxially arranged inclined camming surfaces cooperable with the movable contacts to shift them counter said bias away from the stationary contact means, said su-rfaces arranged in two pairs with the surfaces of one pair 

1. AN ELECTRIC SWITCH COMPRISING: A HOUSING, A STATIONARY CONTACT IN THE HOUSING, A MOVABLE CONTACT SUPPORTED IN THE HOUSING FOR MOVEMENT TOWARD AND AWAY FROM THE STATIONARY CONTACT AND YIELDINGLY BIASED THERETOWARD TO MAKE A CIRCUIT THEREWITH, A CONTAT SHIFTING PART SUPPORTED FOR MOVEMENT IN THE HOUSING AND HAVING AN INCLINED CAMMING SURFACE COOPERABLE WITH THE MOVABLE CONTACT TO SHIFT THE SAME AWAY FROM THE STATIONARY CONTACT UPON MOVEMENT OF THE CAM, AND MECHANISM FOR CONTROLLABLY SHIFTING SAID PART DISPOSED EXTERNALLY AT OPPOSITE SIDES OF AND REMOVABLY SECURED TO THE HOUSING AND HAVING PORTIONS TELESCOPICALLY REMOVABLY CONNECTED WITH OPPOSITE ENDS OF THE CONTACT SHIFTING PART. 